反应详情

To a solution of diisopropylamine (9.0 ml, 64.21 mmol) in 100 ml of anhydrous diethyl ether was added 2.5 M n-BuLi in hexane (20.5 ml, 51.2 mmol) at room temperature. After stirring at room temperature for 30 min, the resulting LDA solution was cooled to −76° C. A solution of 3-hexylthiophene (8.617 g, 51.2 mmol) in 100 ml of diethyl ether was cooled to −76° C. and added to the above LDA solution. The temperature was allowed to rise slowly to −40° C., whereupon it was stirred for 1 h. The solution was then recooled to −76° C. and trimethylborate (8.6 ml, 76.8 mmol) was added slowly. The mixture was allowed to warm to room temperature and stirred for 2 h. After quenching with 10% HCl (100 ml) the organic layer was separated and the aqueous layer was extracted with ether (2×). The combined organic layer was dried over MgSO4, filtered and concentrated. The residue was added 1,3-propanediol (3.7 ml, 51.2 mmol) and refluxed for 2 h. The mixture was then placed directly on a silica column and eluted first with hexane, then chloroform to give the product, 2.82 g, 22%. 1H NMR (CDCl3-d3, 500 MHz): δ 7.36 ppm (s, 1 H), 7.13 ppm (s, 1 H), 4.14-4.12 ppm (t, 4 H, J=8.6 Hz), 2.60-2.63 ppm (t, 2 H, J=8.6 Hz), 2.04 ppm (m, 2 H), 1.60 ppm (m, 2H), 1.28 ppm (m, 4 H), 0.87 ppm (t, 3 H, J=7.5 Hz); 13C-NMR (CDCl3, 500 MHz): δ 144.9, 137.2, 126.8, 126.7, 62.50, 32.09, 31.04, 30.48, 29.38, 27.87, 22.99, 14.46 ppm. EI, MS m/z (%): 252 (100, M+).

1. customto rise slowly to −40° C., whereupon it
2. stirringwas stirred for 1 h
3. customwas then recooled to −76° C.
4. temperatureto warm to room temperature
5. stirringstirred for 2 h
6. customAfter quenching with 10% HCl (100 ml) the organic layer
7. customwas separated
8. extractionthe aqueous layer was extracted with ether (2×)
9. dry with materialThe combined organic layer was dried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated
12. temperaturerefluxed for 2 h
13. washeluted first with hexane
14. customchloroform to give the product, 2.82 g, 22%